Ukraine's President Petro Poroshenko has reached agreement with Russia's Vladimir Putin on Wednesday on a "permanent ceasefire" in eastern Ukraine's Donbass region, Poroshenko's press office said in a statement, Reuters reported.

"Mutual understanding was achieved concerning the steps which will enable the establishment of peace," the statement also said after Poroshenko and President Putin spoke by telephone.

Rebels are battling Kiev's forces in the mainly Russian-speaking Donbass region, which is home to most of Ukraine's heavy industry and accounts for about 18 percent of the country's economic output.